Know your skin.
Spot change early.
A plain-English guide to melanoma: what it is, who is at risk, how to check your moles, and when to see a doctor.
What is melanoma?
A type of skin cancer that develops in melanocytes, the cells that produce melanin (pigment).
Melanoma can develop in an existing mole or appear suddenly as a new dark spot.
It is less common than other skin cancers, but it causes most skin cancer deaths because it is more likely to spread to other parts of the body.
Caught early, it is usually highly treatable, often with a small operation.
From sunshine to mutation
Melanoma starts when DNA damage in skin cells triggers mutations. The main cause of that damage is ultraviolet (UV) radiation from sunshine or sunbeds.
Types of melanoma
Most people picture a dark, irregular mole. Some melanomas look very different, so it helps to know the main types. Select one to explore.
Risk factors for melanoma
Anyone can develop melanoma. Some things raise the chance. Having a risk factor does not mean you will get it, and having none does not mean you won't.
Sun exposure
A history of blistering sunburns, or high cumulative UV exposure over the years, including from sunbeds.
Physical traits
Fair skin (see the Fitzpatrick scale below), light hair or eyes, freckles, or a high number of moles (over 50).
Genetics
A family history of melanoma, or having had melanoma or another skin cancer yourself.
Immune system
A weakened immune system. This includes older people, those with certain medical conditions, and organ transplant recipients.
The Fitzpatrick scale: how your skin reacts to sun
Dermatologists group skin by how easily it burns and tans. Choose a type to see what it means.
The five stages, layer by layer
Doctors stage melanoma by how thick it is, whether the surface is ulcerated, and whether it has reached lymph nodes or other organs. Move through the stages to see how it grows.
Early detection can save your life
Five-year survival falls as melanoma grows deeper and spreads. These are averages for large groups of people, not a prediction for any one person.
Five-year survival by stage at diagnosis
Sources: Stages 1–3: Cancer Research UK, using NHS England data (net survival). Stage 4: SEER (USA), 5-year relative survival for distant-stage melanoma, 2016–2022, because NHS England does not publish a stage 4 figure that reflects newer treatments. Stage 0 is shown with stage 1 because it is confined to the top skin layer. Immunotherapy and targeted therapy have improved outcomes for advanced melanoma: in one clinical trial of combined immunotherapy, roughly 45–55% of people were alive after 6.5 years. Individual outcomes vary.
Early detection can be the difference between a simple procedure and a life-threatening disease. When caught at its earliest stages, melanoma is highly treatable, often before it has had the chance to grow deeper, spread to lymph nodes or reach vital organs.
But melanoma can be aggressive and unpredictable. Delaying action gives it time to advance silently beneath the skin.
Learn the ABCDE signs
Dermatologists use the ABCDE method to spot a mole that may be malignant. Drag the sliders to see what each sign looks like on a made-up mole.
An illustration only. Not a tool for checking your own moles.
Asymmetry
One half of the mole doesn't match the other.
Border
Irregular, blurred, ragged or notched edges.
Colour
Made up of multiple colours or shades.
Diameter
Larger than 6 mm (about a pencil eraser, 0.25 inches).
Evolving
Changing over time in size, shape or colour.
🔎 Beyond ABCDE
Features such as itching, dryness, crusting, ulceration or bleeding should not be ignored either.
- A sore that does not heal
- A new mole or spot that appears in adulthood
- A dark streak under a nail that wasn't caused by injury
🧱 Nodular moles
Nodular moles can be benign or malignant, but deserve careful attention because nodular melanoma is one of the more aggressive forms. It can be pink, red or skin-coloured, so ABCDE may miss it. Think EFG:
🦆 The "ugly duckling"
Most of your moles look alike. One that looks different from the rest deserves a closer look, even if it doesn't tick the ABCDE boxes.
Check your skin every month
Checking monthly, and keeping a mole diary with photos, dates and notes, turns memory into evidence. It helps you notice slow changes and share clear information with a healthcare professional.
Your 8-step skin check
Use a full-length mirror and good light, and a hand mirror for your back. Tap each area as you go. Nothing is saved.
Track a mole over time
🔒 Private by design: entries and photos stay in this browser on this device. They are never uploaded to FatCube AI or anyone else. Clearing your browser data will remove them, so download a backup if you want to keep a copy.
Smart sun habits, every day
Prevention starts with protecting your skin daily, not just on sunny holidays. Tap a card to flip it.
How much sunscreen is enough?
Most people put on far too little. As a guide, an adult covering their whole body needs about 6–8 teaspoons (around 35 ml). Press the button to see it build up.
0 of 8 teaspoons applied.
- Choose SPF 30 or higher and a broad-spectrum (UVA) rating. In the UK, look for 4 or 5 UVA stars.
- Reapply at least every 2 hours, and after swimming, sweating or towel-drying.
- Sunscreen is one layer of protection. It does not replace shade and clothing.
Harmless or harmful? Looks can fool you.
Benign moles are usually small, round or oval, symmetrical and evenly coloured, with smooth, well-defined borders, and they tend to stay stable. Melanomas are more likely to look irregular, or to change.
✅ Benign mole (naevus) tends to be
- Small, round or oval
- Symmetrical
- One even colour
- Smooth, well-defined edge
- Stable over time
⚠️ Malignant mole may be
- Irregular or asymmetrical
- Uneven, notched or blurred at the edges
- Varied in colour
- Larger (over 6 mm)
- Changing in any way
Examples (tap to enlarge)
Can you tell the difference?
Look at the image and decide: is it a benign mole or a melanoma?
As soon as something changes
See a doctor as soon as you notice a mole or skin lesion that is new, changing or unusual. Even spots that don't fit the typical rules can be dangerous, especially if they evolve.
What happens next? (typical UK pathway)
Book an appointment with your GP
Tell them what has changed and when. Bring your mole diary and photos if you have them.
Urgent referral if skin cancer is suspected
If your GP is concerned, you are usually referred urgently to a skin specialist, often within about two weeks.
Specialist examination
A dermatologist looks closely at the spot, often using a handheld magnifier called a dermatoscope.
Removal and tests if needed
A suspicious mole is usually removed and sent to a laboratory. Most removed moles turn out not to be melanoma.
Pathways and waiting times differ between countries and health systems. If you are outside the UK, ask your local doctor how referral works.
Common myths about melanoma
Tap a card to reveal the truth.
Trusted sources and support
For detailed, up-to-date information and support, these organisations are a good place to start.
Statistics: Cancer Research UK (NHS England net survival by stage) and the US National Cancer Institute SEER programme (2016–2022). Staging follows the AJCC 8th edition, simplified. Page last updated October 2026.
Disclaimer
This information is for educational purposes and does not constitute medical advice. It cannot diagnose any skin condition. Always consult a healthcare professional for diagnosis or concerns about skin health.